Radar sensor

Abstract

A radar sensor (1) is attached to a box body (100) defining a storage space (S). The radar sensor (1) is configured to detect an object (103) by irradiating the object (103) disposed in the storage space (S) with a radio wave (R) and detecting reflection of the radio wave (R) from the object (103).

Description

Radar Sensor

[0001] The present invention relates to a radar sensor.

[0002] For example, Patent Document 1 discloses a technique in which an ultrasonic sensor is attached to the housing of a trash can, and the amount of trash inside the trash can is detected by the ultrasonic sensor.

[0003] JP 2012-101865 A

[0004] Ultrasonic sensors are susceptible to temperature and humidity, for example, and if the trash can is installed outdoors, the accuracy of measuring the amount of trash can may vary depending on the temperature and humidity.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a radar sensor that can detect an object inside a box with high accuracy.

[0006] A radar sensor according to one aspect of the present invention is a radar sensor attached to a box that defines an accommodation space, and is configured to detect an object placed in the accommodation space by irradiating the object with radio waves and detecting the reflection of the radio waves from the object.

[0007] According to the present invention, it is possible to provide a radar sensor that can detect an object inside a box with high accuracy.

[0008] 1 is a perspective view, seen from above, schematically illustrating the structure of a radar sensor 1 according to an embodiment of the present invention. FIG. 2 is a perspective view, seen from below, schematically illustrating the structure of a radar sensor 1 according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1. FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 1. FIG. 5 is an exploded perspective view, seen from above, of the radar sensor 1 with the protective member 12 removed from the housing 10. FIG. 6 is an exploded perspective view, seen from below, of the radar sensor 1 with the protective member 12 removed from the housing 10. FIG. 7 is an exploded perspective view of the radar sensor 1 according to an embodiment of the present invention. FIG. 8 is a perspective view, seen from above, of the radar sensor 1 with a bracket 22 attached to the housing 10. FIG. 9 is a cross-sectional view of the radar sensor 1, schematically illustrating the mounting structure of the circuit board 30. FIG. 10 is an enlarged partial cross-sectional view, seen from above, schematically illustrating the structure of the lens 16. FIG. 11 is an enlarged partial cross-sectional view, seen from above, schematically illustrating the structure of a switch 40 mounted on the circuit board 30. FIG. 12 is an enlarged partial cross-sectional view of the circuit board 30 with the switch 40 mounted on it. FIG. 13 is a cross-sectional view, seen from above, schematically illustrating the structure of a box 100 according to another embodiment of the present invention.

[0009] An embodiment of the present invention will be described below with reference to the accompanying drawings. Fig. 1 is a perspective view showing a schematic structure of a radar sensor 1 according to an embodiment of the present invention, as viewed from above. Fig. 2 is a perspective view showing a schematic structure of a radar sensor 1 according to an embodiment of the present invention, as viewed from below.

[0010] As will be described later, the radar sensor 1 is incorporated into a box (not shown), such as an outdoor or indoor trash can. Specifically, the box has a base that defines a storage space and a lid that is attached to the base and closes the storage space. The radar sensor 1 is attached to, for example, the inner surface of the lid. The radar sensor 1 can detect an object by irradiating radio waves into the storage space and detecting the radio waves reflected from the object in the storage space. Note that up and down in the following description do not necessarily correspond to up and down in the direction of gravity.

[0011] 1 and 2, the radar sensor 1 has a housing 10 having, for example, a generally flat rectangular parallelepiped outer shape. The housing 10 defines an upper surface 10a and a lower surface 10b that face each other, and four side surfaces 10c to 10f that connect the upper surface 10a and the lower surface 10b to each other. The side surfaces 10c and 10e face each other, and the side surfaces 10d and 10f face each other. In this example, the upper surface 10a and the lower surface 10b are defined parallel to each other. Furthermore, the side surfaces 10c and 10e, as well as the side surfaces 10d and 10f, are inclined so as to approach each other from the lower surface 10b toward the upper surface 10a.

[0012] Four fixing members 11 are arranged on the top surface 10a of the housing 10, adjacent to the four corners of the housing 10. The fixing members 11 are, for example, screws. The fixing members 11 are screwed into the housing 10 from the top surface 10a toward the bottom surface 10b of the housing 10. The heads 11a of the fixing members 11 are exposed on the top surface 10a of the housing 10. For example, when the inner surface of a lid of a box body is horizontal, the four fixing members 11 are used to fix the housing 10, i.e., the radar sensor 1, to the inner surface of the lid. Specifically, as described below, the fixing members 11 are screwed into the housing 10 through holes formed in the lid with the top surface 10a of the housing 10 abutting against the inner surface of the lid.

[0013] A protective member 12 is attached to the bottom surface 10b of the housing 10, covering almost the entire bottom surface 10b. A protective member 13, for example, having an annular shape, is arranged between the top surface 10a of the housing 10 and the head 11a of the fixing member 11. Furthermore, protective members 14 are arranged on the top surface 10a of the housing 10 at positions adjacent to the side surfaces 10d and 10f of the housing 10. The protective member 14 is formed, for example, into a rectangle in a plan view. Furthermore, protective members 15 are arranged on the side surfaces 10d and 10f of the housing 10, adjacent to the protective member 14. The protective members 15 are formed, for example, into a rectangle in a plan view.

[0014] The protective member 12 has an outline larger than the outline of the lower surface 10b in a bottom view. The peripheral edge of the protective member 12, extending outward from the outline of the lower surface 10b, covers a portion of the lower ends of the side surfaces 10c to 10f. As shown in FIG. 2 , the protective member 12 is formed with a first opening 12a, e.g., circular in plan view, a second opening 12b, e.g., rectangular in plan view, and a third opening 12c adjacent to the first opening 12a. A lens 16 is exposed in the first opening 12a. A label (not shown), for example, attached to the lower surface 10b of the housing 10 is exposed in the second opening 12b. A switch (not shown) built into the housing 10 is disposed in the third opening 12c. The switch is, for example, an on / off switch.

[0015] As will be described later, the protective member 12 seals holes, including screw holes, formed on the bottom surface 10b of the housing 10. The annular protective member 13 is sandwiched between the inner surface of the cover to which the radar sensor 1 is attached and the top surface 10a of the housing 10, and seals the screw holes in the housing 10 into which the fixing member 11 is inserted. In addition, the rectangular protective members 14 and 15 seal holes, including screw holes, formed on the top surface 10a and side surfaces 10d and 10f of the housing 10. These protective members 12 to 15 can prevent liquids and the like from entering the housing 10 through holes, including screw holes, formed in the housing 10.

[0016] The protective members 12 to 15 are formed from, for example, an alkali-resistant resin material such as polypropylene (PP), polyethylene terephthalate (PET), or ethylene propylene diene rubber (EPDM). In particular, the protective members 13 to 15 are formed from, for example, a resin sheet having a predetermined thickness. The protective member 12 is formed from, for example, an elastic resin material (e.g., ethylene propylene diene rubber (EPDM)) having a thickness greater than that of the protective members 13 to 15. The protective members 12 to 15 are attached to the housing 10 by, for example, double-sided tape or adhesive.

[0017] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1. FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 1. Referring to both FIGS. 3 and 4, the housing 10 has a lower base (first portion) 17 and an upper cover (second portion) 18 coupled to the base 17. The base 17 defines the lower surface 10b of the housing 10, while the cover 18 defines the upper surface 10a and side surfaces 10c to 10f of the housing 10. In this example, the cover 18 is coupled to the base 17 by six fixing members 19 (see FIG. 4), which are screws that are screwed from the base 17 toward the cover 18.

[0018] As shown in FIG. 3 , the shaft 11b of the fixing member 11 passes through a boss 18b extending downward from the top plate 18a of the cover 18 and extends to a boss 17b extending upward from the bottom plate 17a of the base 17. The shaft 11b of the fixing member 11 is coupled to a nut 20 fixed to the upper end of the boss 17b between the boss 18b and the boss 17b. In this manner, the fixing member 11 is fastened to the housing 10. Meanwhile, as shown in FIG. 4 , the head 19a of the fixing member 19 is disposed in a recess 17c formed in the bottom plate 17a of the base 17. The shaft 19b of the fixing member 19 is screwed into the boss 18c extending downward from the top plate 18a of the cover 18. The base 17 and the cover 18 are formed from a resin material such as polycarbonate.

[0019] FIG. 5 is an exploded perspective view of the radar sensor 1 viewed from above with the protective member 12 removed from the housing 10. FIG. 6 is an exploded perspective view of the radar sensor 1 viewed from below with the protective member 12 removed from the housing 10. Referring to FIGS. 5 and 6 together, a protrusion 12d corresponding to the boss 17b of the base 17 is formed on the inner surface of the protective member 12. As shown in FIG. 3, the protrusion 12d is disposed within the through-hole of the boss 17b. In the housing 10, the areas around the boss 17b and the recess 17c are areas where stress is applied due to the screwing of the fixing members 11 and 19. The protective member 12 seals the recess 17c in which the head 19a of the fixing member 19 is disposed. In this way, the protective member 12 seals the hole formed in the lower surface 10b of the base 17 and covers the area where stress is applied.

[0020] FIG. 7 is an exploded perspective view of a radar sensor 1 according to an embodiment of the present invention. Referring to FIGS. 3, 4, and 7, the base 17 of the housing 10 has a peripheral wall 17d extending upward from the bottom plate 17a and inside the boss portion 17b. Meanwhile, the cover 18 of the housing 10 has a peripheral wall 18d extending downward from the top plate 18a and inside the boss portion 18b. The peripheral wall 17d is disposed on the inner circumferential side of the peripheral wall 18d. That is, the outer circumferential surface of the peripheral wall 18d at least partially faces the outer circumferential surface of the peripheral wall 17d. A gasket 21, such as an O-ring, is disposed between the upper end of the peripheral wall 17d of the base 17 and the top plate 18a of the cover 18. The gasket 21 seals the storage space inside the peripheral wall 17d and the peripheral wall 18d.

[0021] A circuit board 30 is disposed in the storage space inside the peripheral walls 17d and 18d. In this example, the circuit board 30 is disposed parallel to the bottom plate 17a of the base 17 and the top plate 18a of the cover 18. An integrated circuit (IC) chip 31 is mounted on the underside 30a of the circuit board 30. In this example, the IC chip 31 is a radar IC chip. The IC chip 31 is mounted on the circuit board 30 at a position facing the lens 16 formed on the base 17. The IC chip 31 is configured to emit radio waves having a predetermined angle range (e.g., 130 degrees) toward the lens 16. The IC chip 31 is also configured to detect radio waves returning to the IC chip 31 via the lens 16. The circuit board 30 also has mounted thereon a wireless communication circuit (not shown) for transmitting information detected by the IC chip 31, for example, via wireless communication.

[0022] 7, the protective member 15 is configured to seal holes formed in the side surfaces 10d and 10f of the housing 10. As will be described later, these holes include, for example, holes for attaching brackets to the housing 10. In addition, the protective member 14 is configured to seal holes formed in the top surface 10a of the housing 10.

[0023] Fig. 8 is a perspective view of the radar sensor 1 as seen from above, showing the state in which the bracket 22 is attached to the housing 10. As shown in Fig. 8, when attaching the radar sensor 1 to the lid, the bracket 22 may be used instead of the fixing member 11. The bracket 22 is used to adjust the attachment angle of the housing 10 when attaching it to the inner surface of the lid of the box when the inner surface of the lid of the box is not horizontal.

[0024] The bracket 22 is attached to the side surfaces 10d and 10f of the housing 10 by a pair of fixing members 23, 23, which are screws. In this example, the bracket 22 has a pair of rocking pieces 22a, 22a attached to the side surfaces 10d and 10f of the housing 10, respectively, and a connecting piece 22b connecting the rocking pieces 22a, 22a to each other. The rocking pieces 22a, 22a are formed in a plate shape with portions thereof facing the side surfaces 10d and 10f, respectively. Similarly, the connecting piece 22b is formed in a plate shape facing the top surface 10a. The pair of rocking pieces 22a, 22a are attached to the housing 10 so as to be rockable around an axis x1 of the fixing members 23, 23. In this example, the axis x1 is defined, for example, parallel to the top surface 10a, bottom surface 10b, side surface 10c, and side surface 10e of the housing 10.

[0025] Each of the swinging pieces 22a has a slot 22c extending in an arc shape around the axis x1. Screw-shaped fixing members 24 are threaded into the side surfaces 10d and 10f of the housing 10 via the slots 22c. The fixing members 24 can move within the slots 22c when the bracket 22 swings around the axis x1. When the fixing member 23 is fastened to the housing 10 with the fixing member 24 positioned at a predetermined position in the slot 22c, the swinging of the bracket 22 around the axis x1 is restricted. By fastening the fixing members 24 to the swinging pieces 22a at predetermined positions within the slots 22c, the position of the bracket 22 relative to the housing 10 is fixed. The bracket 22 can swing around the axis x1 within an angle range of approximately 45 degrees.

[0026] In this example, the housing 10 is attached to the inner surface of the cover via the bracket 22, eliminating the need for the fixing member 11. Therefore, in this case, the fixing member 11 may be removed from the housing 10. The hole through which the fixing member 11 was inserted is sealed by a protective member 13A, replacing the annular protective member 13 described above. The protective member 13A is formed, for example, in a circular shape in a plan view. The protective member 13A is made of the same material as the protective member 13. Furthermore, openings (not shown) are formed in the protective member 15 to accommodate the insertion of the fixing members 23 and 24, respectively. The openings have diameters similar to the diameters of the shafts of the fixing members 23 and 24, for example. Thus, the protective members 14 and 15 are positioned in the housing 10 around areas where stress acts when the fixing members 23 and 24 are screwed into the cover 18.

[0027] FIG. 9 is a cross-sectional view of the radar sensor 1, schematically illustrating the mounting structure of the circuit board 30. FIG. 9 is a cross-sectional view taken at a position different from FIGS. 3 and 4 . As shown in FIG. 9 , in this example, the circuit board 30 is mounted to the cover 18 using a fixing member 32, such as a screw, attached to a boss 18e extending downward from the top plate 18a of the cover 18. The fixing member 32 passes through a hole 30c formed in the circuit board 30. The upper surface 30b of the circuit board 30 receives the lower end of the boss 18e. A spacer 33 is disposed between the head 32a of the fixing member 32 and the lower surface 30a of the circuit board 30. The spacer 33 is, for example, a cylindrical metal tube. The shaft 32b of the fixing member 32 is screwed into the boss 18e. The spacer 33 positions the head 32a of the fixing member 32 on the inner surface of the bottom plate 17a of the base 17 with a predetermined gap therebetween. In this example, the circuit board 30 is mounted to the cover 18 using two fixing members 32. The fixing member 32 and the spacer 33 constitute the blocking member of the present invention.

[0028] FIG. 10 is a partially enlarged cross-sectional view schematically illustrating the structure of the lens 16. As shown in FIG. 10, the lens 16 is disposed in a recess 17f formed in the bottom plate 17a of the base 17. This recess 17f is exposed in the first opening 12a of the protective member 12. The lens 16 includes a first lens 34 far from the IC chip 31 and a second lens 35 close to the IC chip 31. The first lens 34 is exposed to the external space of the housing 10 through the first opening 12a within the recess 17f. The first lens 34 and the second lens 35 are integrally formed with the bottom plate 17a of the base 17. Specifically, when manufacturing the base 17, for example, two-color molding is performed, in which the second lens 35 is molded first, and then the molded second lens 35 is placed in a mold and the first lens 34 and the bottom plate 17a of the base 17 are molded. In this manner, the first lens 34, the second lens 35, and the base 17 are integrally formed with one another.

[0029] 7 and 10 , the lens 16 is formed by stacking multiple (four in this example) flat cylindrical portions, namely, a first portion 36a, a second portion 36b, a third portion 36c, and a fourth portion 36d, all of which share the same central axis x2. The IC chip 31 is mounted on the lower surface 30a of the circuit board 30 along the central axis x2. The first lens 34 has the first portion 36a and the second portion 36b. The second lens 35 has the third portion 36c and the fourth portion 36d. In this example, the diameters of the first portion 36a, the second portion 36b, the third portion 36c, and the fourth portion 36d decrease stepwise toward the IC chip 31 along the central axis x2. Thus, in the lens 16, the first portion 36a, which has the largest diameter of the four portions, has an annular stepped surface formed around the second portion 36b. Similarly, an annular step surface is formed around the third portion 36c in the second portion 36b, and an annular step surface is formed around the fourth portion 36d in the third portion 36c.

[0030] The radio waves emitted from the IC chip 31 toward the lens 16 over a wide cone (e.g., 130 degrees) are adjusted by the lens 16 to a narrow cone (e.g., 60 degrees). The adjusted narrow-range radio waves are emitted from the lens 16 along the central axis x2. In this adjustment, the distance D between the IC chip 31 and the fourth portion 36d of the lens 16 and the thickness T from the lower surface of the first portion 36a to the upper surface of the fourth portion 36d in the direction along the central axis x2 are adjusted. In this example, the distance D is set to, for example, approximately 5 mm. The thickness T is set to, for example, approximately 10 mm. The distance D is set to be greater than the distance between the fixing member 32 and the bottom plate 17a of the base 17. As is clear from FIG. 10 , the lens 16 is disposed within the recess 17f of the bottom plate 17a of the base 17, and therefore the outer surface of the lens 16, i.e., the first portion 36a, is disposed inward from the outer surface of the protective member 12.

[0031] FIG. 11 is a partially enlarged cross-sectional view schematically illustrating the structure of the switch 40 mounted on the circuit board 30. FIG. 12 is a partially enlarged perspective view of the circuit board 30, schematically illustrating the structure of the switch 40. Referring to FIGS. 11 and 12 together, the switch 40 is mounted on the underside 30a of the circuit board 30. The switch 40 is disposed within a boss portion 17g extending upward from the bottom plate 17a of the base 17. The boss portion 17g has a through-hole 17h that communicates with the external space outside the housing 10 via the third opening 12c of the protective member 12. In other words, the switch 40 within the boss portion 17g is accessible from the external space of the housing 10 via the third opening 12c of the protective member 12. A light-emitting element 41 is also mounted on the underside 30a of the circuit board 30. The light-emitting element 41 may include, for example, a light-emitting diode (LED). The light-emitting element 41 can emit light toward the switch 40 along the underside 30a.

[0032] The switch 40 has a support portion 42 fixed to the lower surface 30a of the circuit board 30 and a deformation portion 43 supported by the support portion 42. The support portion 42 has a generally annular base end 44 and a cylindrical tip end 45 rising from the base end 44. The base end 44 is attached to the lower surface 30a of the circuit board 30. The tip end 45 is formed cylindrically around the axis x3. The outer peripheral surface 45a of the tip end 45 may be formed as a tapered surface that decreases in diameter from the base end continuing to the base end 44 toward the tip end. The base end 44 and the tip end 45 are formed, for example, from a resin material having a predetermined hardness. The resin material is formed, for example, from a transparent or translucent material that can guide light from the light-emitting element 41. In this example, a protrusion 44a protruding from the base end 44 to the outer periphery along the lower surface 30a is received by the upper end of the boss portion 17g.

[0033] The deformation portion 43 includes a shaft portion 46 disposed within the tip portion 45 of the support portion 42, an elastic deformation portion 47 connected to the shaft portion 46, and a tubular portion 48 connected to the elastic deformation portion 47. In this example, the shaft portion 46 is formed in a cylindrical shape centered on the axis x3. A conductor 46a is formed at one end, i.e., the upper end, of the shaft portion 46. In this example, the conductor 46a is formed over the entire surface of the upper end of the shaft portion 46. Meanwhile, a conductive pattern 30d is formed on the lower surface 30a of the circuit board 30 at a position facing the conductor 46a. The conductive pattern 30d is formed, for example, from two conductive patterns formed to interlock with each other in a comb-like shape. As described below, when the shaft portion 46 is displaced toward the circuit board 30 along the axis x3 and the conductor 46a at the upper end of the shaft portion 46 comes into contact with the conductive pattern 30d, electrical continuity is established between the two conductive patterns. This establishment of electrical continuity switches the radar sensor 1 on and off.

[0034] The other end, i.e., the lower end, of the shaft portion 46 expands annularly in a radial direction perpendicular to the axis x3. The elastic deformation portion 47 extends cylindrically from the annular portion at the lower end of the shaft portion 46 in a direction along the axis x3. In this example, the elastic deformation portion 47 is formed cylindrically centered on the axis x3. The outer peripheral surface of the elastic deformation portion 47 faces the inner peripheral surface of the through hole 17h. Meanwhile, the inner peripheral surface of the elastic deformation portion 47 faces the outer peripheral surface of the shaft portion 46. As described below, when the lower end of the shaft portion 46 is pressed toward the circuit board 30, the elastic deformation portion 47 elastically deforms, expanding outward and buckling. As a result, the length of the elastic deformation portion 47 in the direction of the axis x3 decreases, allowing the shaft portion 46 to displace toward the circuit board 30. In this way, the conductor 46a at the upper end of the shaft portion 46 can contact the conductive pattern 30d on the lower surface 30a of the circuit board 30.

[0035] The tubular portion 48 extends cylindrically from the upper end of the elastically deforming portion 47 in a direction along the axis x3. In this example, the tubular portion 48 is formed cylindrically centered on the axis x3. The radial thickness of the tubular portion 48 is greater than the radial thickness of the elastically deforming portion 47. The inner circumferential surface 48a of the tubular portion 48 contacts the outer circumferential surface 45a of the tip end 45 of the support portion 42. Meanwhile, the outer circumferential surface 48b of the tubular portion 48 contacts the inner circumferential surface of the through hole 17h of the boss portion 16g. A protrusion 48c protruding outward is formed on the outer circumferential surface 48b of the tubular portion 48. In this example, the protrusion 48c is formed in an annular shape around the axis x3. In a cross section taken along an imaginary plane including the axis x3, the protrusion 48c has, for example, an arc-shaped contour that protrudes outward from the outer circumferential surface 48b. The outer diameter of the tubular portion 48, defined by the outer circumferential end of the protrusion 48c, is set to be greater than the inner diameter of the inner circumferential surface of the through hole 17h. As a result, the cylindrical portion 48 is compressed and sandwiched between the outer peripheral surface 45a of the tip portion 45 of the support portion 42 and the inner peripheral surface of the through hole 17h.

[0036] As is clear from FIG. 11 , the lower end of the tubular portion 48 is received on an annular stepped surface 17i formed on the inner circumferential surface of the through-hole 17h. Meanwhile, the upper end of the tubular portion 48 is received on the lower surface of the base end portion 44 of the support portion 42. Thus, displacement of the tubular portion 48 in the direction of the axis x3 is restricted. The shaft portion 46, the elastically deforming portion 47, and the tubular portion 48 are integrally formed. Specifically, the deforming portion 43 is integrally formed from an elastic resin material such as silicone. After molding the deforming portion 43, a conductor 46a is formed on the upper end of the shaft portion 46 by, for example, applying a conductive paint. The elastic resin material is formed, for example, from a transparent or translucent material capable of guiding light from the light-emitting element 41. In this example, light emitted from the light-emitting element 41 along the lower surface 30a toward the switch 40 is guided to the support portion 42 and the deforming portion 43. Since the switch 40 in the through-hole 17h is visible from the external space, the light guided by the support portion 42 and the deformation portion 43 makes the light of the light-emitting element 41 visible from the external space.

[0037] To switch the radar sensor 1 on and off, a rod-shaped member, for example, is inserted from the external space into the through-hole 17h of the housing 10. When the tip of this member presses the lower end of the shaft portion 46 of the deformation portion 43 toward the circuit board 30, the elastic deformation portion 47 buckles and elastically deforms, expanding outward. The reduction in the length of the elastic deformation portion 47 in the direction of the axis x3 causes the shaft portion 46 to displace toward the circuit board 30. As a result, the conductor 46a at the upper end of the shaft portion 46 contacts the conductive pattern 30d. Conduction is established between the two conductive patterns in the conductive pattern 30d. This conduction switches the radar sensor 1 on and off. The cylindrical portion 48 of the deformation portion 43 is compressed between the tip portion 45 of the support portion 42 and the inner circumferential surface of the through-hole 17h of the boss portion 17g, preventing water and other contaminants from entering the housing 10 through the through-hole 17h. The light emitting element 41 may be configured to irradiate the switch 40 with light when the radar sensor 1 is turned on, for example.

[0038] Next, a usage mode of the radar sensor 1 will be described. FIG. 13 is a cross-sectional view schematically illustrating the structure of a box 100 according to one specific example. The box 100 is, for example, a trash can placed indoors or outdoors. The box 100 has a base 101 that defines a storage space S and a lid 102 that is attached to the base 101 and closes the storage space S. The lid 102 is configured to be openable and closable, for example, by a hinge. In this example, the radar sensor 1 is attached to the inner surface of the lid 102. In this example, the inner surface of the lid 102 is formed as a horizontal surface, and therefore the radar sensor 1 is fixed to the lid 102 by a fixing member 11 that penetrates the lid 102. In the radar sensor 1, the central axis x2 of the lens 16 is defined along the vertical direction. That is, the lower surface 10b of the housing 10 is defined along a horizontal plane.

[0039] In the radar sensor 1, radio waves R are radiated from the IC chip 31 to the lens 16, and after the irradiation range is adjusted by the lens 16, the radio waves R are radiated from the lens 16 toward the object 103. The object 103 is, for example, garbage placed in the storage space S. The radio waves R are reflected from the object 103 and detected by the IC chip 31 via the lens 16. This reflection of the radio waves R allows the radar sensor 1 to detect the amount of objects 103 in the storage space S. Data on the detected amount of objects 103 is transmitted to, for example, a cloud server via a wireless circuit or the like mounted on the circuit board 30. By collecting data on the amount of garbage in the boxes 100 in various locations, garbage collection companies and the like can efficiently collect garbage from garbage bins with large amounts of garbage, for example.

[0040] The radar sensor 1 described above uses radio waves R to detect objects 103, such as dust, within the storage space S of the box 100. Because detection using radio waves R is not easily affected by changes in temperature, humidity, and the like, the radar sensor 1 can detect the objects 103 with high accuracy. However, the radar sensor 1 may become contaminated by dust and other contaminants. To remove the contaminants, for example, an alkaline detergent is used. The housing 10, made of a resin material such as polycarbonate, is vulnerable to alkaline conditions. However, protective members 12-15 are disposed around areas of the housing 10 where stress is applied. These protective members 12-15 can prevent detergent from remaining on the surface of the housing 10 or from penetrating into the housing 10 or screw holes. Therefore, the occurrence of cracks in the housing 10 can be suppressed. In particular, the protective member 12 having a predetermined thickness can protect the housing 10 from impacts that may occur when an object comes into contact with the radar sensor 1 within the box 10.

[0041] In the lens 16, the first lens 34 having a cylindrical first portion 36a and a second portion 36b and the second lens 35 having a cylindrical third portion 36c and a fourth portion 36d are integrally formed by two-color molding. The second lens 35, which has a smaller volume, is molded separately, and then the first lens 34 and the base 17, which have a larger volume, are molded. As a result, sink marks are prevented compared to, for example, when the first lens 34 and the second lens 35 are molded simultaneously, and a lens 16 with a more uniform thickness can be molded. When the first lens 34 and the second lens 35 are molded simultaneously, the volume inside the mold is larger, making it difficult to mold a material with a uniform thickness in the region where the lens 16 is molded. For example, if the thickness T of the lens 16 increases, voids or the like may form. Two-color molding can eliminate such problems.

[0042] Furthermore, within the housing 10, the circuit board 30 is attached to the cover 18 by a fixing member 32 that screws into a boss portion 18e of the top plate 18a of the cover 18. A spacer 33, made of, for example, metal, is disposed between the head 32a of the fixing member 32 and the circuit board 30. The distance between the head 32a of the fixing member 32 and the bottom plate 17a of the base 17 is smaller than the distance D between the IC chip 31 and the lens 16. Therefore, even if an object such as the target object 103 hits the bottom plate 17a of the base 17 and causes the bottom plate 17a to bend toward the circuit board 30, the bottom plate 17a is first received by the head 32a of the fixing member 32. As a result, contact between the IC chip 31 and the lens 16 can be avoided, thereby preventing damage to the IC chip 31 or the lens 16.

[0043] Fig. 14 is a cross-sectional view schematically illustrating the structure of a box 100 according to another specific example. In this box 100, the inner surface of the lid 102 is not defined along a horizontal plane. Therefore, the radar sensor 1 is fixed to the lid 102 via a bracket 22. Specifically, the attitude of the radar sensor 1 is established by adjusting the angle of the bracket 22 relative to the housing 10. The bracket 22 is attached to the lid 102, for example, with screws. The other configuration of the box 100 is similar to that of the box 100 shown in Fig. 13, so the same reference numerals are used for the same configuration and redundant description will be omitted here.

[0044] Although the present invention has been described above through the above embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0045] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. Furthermore, the above-described embodiments do not limit the scope of the present invention, and the present invention may include any and all applications. The components of the above-described embodiments, as well as their arrangement, materials, conditions, shape, and size, are not limited to those illustrated and may be modified as appropriate. For example, the present invention includes variations that arise during implementation due to manufacturing tolerances, etc. Furthermore, components illustrated in different embodiments may be partially substituted or combined within the scope of technical inconsistency. Furthermore, the various configurations may be selectively combined as appropriate to achieve at least some of the aforementioned problems and effects.

[0046] 1 radar sensor, 10 housing, 10a upper surface, 10b lower surface, 10c to 10f side surface, 11 fixing member, 11a head, 11b shaft portion, 12 protective member, 12a first opening, 12b second opening, 12c third opening, 12d protrusion, 13, 14, 15 protective member, 16 lens, 17 base (first part), 17a bottom plate, 17b boss portion, 17c recess, 17d boss portion, 17e peripheral wall, 17f recess, 17g through hole, 17h boss portion, 17i step surface, 18 cover (second part), 18a top plate, 18b boss portion, 18c peripheral wall, 18d boss portion, 19 fixing member, 19a head, 19b shaft portion, 20 nut, 21 gasket, 22 bracket, 22a swing piece, 22b connecting piece, 22c elongated hole, 23, 24 fixing member, 30 circuit board, 30a lower surface, 30b upper surface, 30c hole, 30d conductive pattern, 31 integrated circuit (IC) chip, 32 fixing member, 32a head, 32b shaft portion, 33 spacer, 34 first lens, 35 second lens, 36a first portion, 36b second portion, 36c third portion, 36d fourth portion, 40 switch, 41 light-emitting element, 42 support portion, 43 deformation portion, 44 base end portion, 44a convex portion, 45 tip portion, 45a outer peripheral surface, 46 shaft portion, 46a conductor, 47 elastic deformation portion, 48 cylindrical portion, 48a inner peripheral surface, 48b outer peripheral surface, 48c protrusion portion, 100 box body, 101 Base, 102 Cover, D Distance, R Radio wave, S Storage space, T Thickness, x1 Axis, x2 Central axis, x3 Axis

Claims

1. A radar sensor attached to a box defining an accommodation space, the radar sensor configured to detect an object placed in the accommodation space by irradiating the object with radio waves and detecting the reflection of the radio waves from the object.

2. The radar sensor according to claim 1, comprising: an integrated circuit that emits the radio waves; and a lens that adjusts the irradiation range of the radio waves emitted from the integrated circuit.

3. The radar sensor according to claim 2, wherein the lens is a lens in which a plurality of cylindrical sections having the same central axis are stacked, and the diameters of the plurality of cylindrical sections decrease as they move toward the integrated circuit along the central axis.

4. The radar sensor according to claim 3, wherein the lens comprises a first lens farther from the integrated circuit and a second lens closer to the integrated circuit, and the first lens and the second lens are formed by two-color molding.

5. The radar sensor according to claim 2, comprising: a circuit board on which the integrated circuit is mounted; and a housing that houses the circuit board, wherein the lens is integrally formed with the housing.

6. The radar sensor according to claim 5, further comprising a blocking member disposed between the housing and the circuit board to block deformation of the housing in a direction toward the circuit board.

7. A radar sensor as described in claim 6, comprising a switch mounted on the circuit board, the switch comprising: two conductive patterns formed on the circuit board; and a deformation portion that is elastically deformable within a through-hole formed in the housing, wherein elastic deformation of the deformation portion causes a conductor formed at the tip of the deformation portion to come into contact with the two conductive patterns, thereby establishing conduction between the two conductive patterns.

8. A radar sensor as described in claim 7, wherein the deformation portion has: a shaft portion having an axis and having the conductor at one end; a tubular portion surrounding the shaft portion; and an elastic deformation portion displacing the shaft portion in the direction of the axis by elastic deformation between the shaft portion and the tubular portion; and the switch further has a tubular support portion disposed within the tubular portion, which clamps the tubular portion between itself and the inner surface of the through hole of the housing so as to compress the tubular portion.

9. The radar sensor according to claim 8, wherein the outer diameter of the cylindrical portion is larger than the inner diameter of the inner peripheral surface of the through hole.

10. The radar sensor according to claim 8, further comprising a protrusion protruding outward from the outer circumferential surface of said cylindrical portion.

11. The radar sensor according to claim 8, further comprising a light-emitting element mounted on the circuit board, and the switch is configured to guide light emitted from the light-emitting element to the outside of the housing through the through-hole.

12. The radar sensor according to claim 5, wherein the housing has a first part and a second part that are joined to each other via a fixing member, and the housing is provided with a protective member that covers areas of the first part and the second part where stress acts.

13. The radar sensor according to claim 12, wherein the area where the stress acts is an area around the fixing member.

14. The radar sensor according to claim 12, further comprising a bracket for attaching the housing to an object to be attached, and the area on which the stress acts is the area on the housing where the bracket is attached.

15. The radar sensor according to claim 12, wherein the protective member is formed from an alkali-resistant material.

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